Sulfurio acid carbonizing of wool flannel



United States Patent MOTHPROOFIN G WITH SOLUBLE I DICYANAMIDES Bruce D. Gleissner, Old Greenwich, and Daniel E. Nagy, Stamford, Conn., assignors to American Cyanamid Company, New York, N. Y., a corporation of Maine No Drawing. Application September 12, 1951, Serial No. 246,344

Claims. (Cl. 8-94.14)

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with the dicyanamides. The treatment is not limited to wool, but is also effective, for example, on the hair or fur of the goat, camel, seal, rabbit .(e. g., felted hats), llama, vicufia, alpaca, cow, horse, muskrat, squirrel, fox, skunk, and the like. .In fact the process of this invention is applicable to virtually any fibrous keratinaceous material, including human hair (as in wigs) and even feathers, However, the invention is especially concerned with the treatment of woolen textiles, e. g., woolen yarns and cloth or fabric, raw wool and the like, as well as wool-containing textiles in which the wool is blended with other fibers, e. g., cellulosic fibers including cotton fibers.

The result of such treatment as above described (after residual soluble salt is washed out) is that no detectable in such a way that they are rendered repellent and subtion is to provide a process that results in substantially permanent mothproofing. Another object is to impart moth repellency to animal fibers, and more particularly to wool, that is not removed by repeated washings and/or dry cleanings. A still further object of the invention is to provide an odorless, light-stable moth-proofed fabric. Another object of the invention is to provide a mothproofing process that does not weaken or otherwise adversely afiect the fabric, and which can be used in conjunction with other conventional fabric treating steps. These and other objects are accomplished by treating animal fibers with a water-soluble dicyanamide salt. 1

A large number of mothproofing processes and agents are known. All of these, however, are subject to disadvantages, and only a few are of practical value. The ideal mothproofing agent should provide an odorless fabric that does not lose its moth-repellency under home storage conditions, not under'exposure to sunlight, nor by repeated washings or dry cleanings. And it should be inexpensive. So far as is known, water-soluble di-' cyanamide salts are the only mothproofing agents;

meeting all of these requirements. Other commercial mothproofing preparations are believed inadequate in one or more respects. For example, fabrics treated with silicofluorides lose their repellency to moth larvae after the fabric is washed. The alkaloid type of preparation (cinchona, rotenone, etc.) is not removed by washing but is removed by dry cleaning, and also the fabric loses repellency when exposed to sunlight. Possibly the best all around mothproofing agents on the market prior to applicants discovery were. Mitin FFand the Eulans, which are said ,to give a. light-stable, odorless fabric that can be both washed and dry cleaned several times. These materials, however, must be applied to the fabric in a hot dye bath during the manufacture of the fabric, and consequently are not available to the home user. Furthermore, they are relatively expensive in comparison to the metal dicyanamides. Water-soluble dicyanamide salts can be applied to the fabric at any time, in the mill or in the home, in hot or cold solution, and before, afteror during conventional textile treating processes.

Numerous animal-fiber products, such as yarns, fabrics, upholstery, carpets, and the like can be moth-proofed dicyanamide in either the free form or in the form of a salt remains on the wool. I r

The. mechanism of the process is not-clearly understood. However, it is evident that some;of the dicyanamide salt reacts chemicallywith the fiber and/or polymerizes on the fiber in such a way that the dicyanamide material is not removed by any known solvent. Thus, when a woolen textile is subjected to an aqueous solution of a dicyanamide salt so that the wool picks up a few percent (e. g., 4%) of its weight -of such dicyanamide salt, the textile canbe washed to remove most of the salt (e. g. 907 but the remaining very small amount of salt cannot 'be removed. Consequently, the repellency of the textile is due not to a dicyanamide salt, but to the fiber structure resulting from the reaction of a very small amount of dicyanamide salt with the wool itself, chemically and/or mechanically. Sometimes the nitrogen pickup in the wool resulting from treatment with a dicyanamide salt is so small as to be undetectable by normal methods of nitrogen analysis. Such treated textile is, however, just as repellent to moth larvae as woolen textiles that have picked up enough nitrogenous compound during the process to show increment when subjected to nitrogen analysis.

According to this invention, any water-soluble dicyanamide salt can be used in the moth proofing process. Such salts are the sodium, potassium, ammonium, calcium, magnesium, barium, and lithium dicyanamides. Any of these can be used in place of the ammonium dicyanamide on which most of the examples herein are based. The ammonium salt is however the preferred material. a 1

The following examples illustrate without limiting the invention. p v i I EXAMPLE 1 Dip-p'ad application A 4% aqueous solution of ammonium dicyanamide was made up by dissolving 8 g. of ammonium dicyanamide in 200 cc. of water at room temperature. (The ammonium dicyanamide is quite soluble and dissolves readily with a little'stir'ring. If the ammonium dicyanamide contains water-insoluble impurities, the resulting solution is preferably filtered.) A 9"x23 piece of 8 ounce wool flannel was immersed in the 200 cc. soluto a wet pickup of about 100% to provide an ammonium dicyanamide weight pickup of about 4%, based on the;

weight of the-cloth, which was then framed to size and dried. The wet cloth can be simply air dried at room temperature, but preferably a hot draft is used, e. g.,

F. to 290 F. Optimum drying is generally 9 minutes at 250 F., but this will vary, of course, depending on the amount of water pick-up, thickness of fabric, and other factors.

After drying, sq. in. circular samples were cut from the cloth and moth repellency determined in the conventional way, that is, by exposingeach sample (in a Petri dish) to'the action of 10 carpet beetle larvae for a period of 2 weeks. Quantitative values were-obtained by weighing the excrement (known as frass) of the larvae produced during this period. In this procedure, tests giving 3.0 mg. or less of frass per sample are considered to indicate efficient mothproofing. It has been found that the flannel samples of Example 1 and all other woolen samples similarly prepared almost always pro vided frass less than 3.0 -mg., even after several washings, several dry cleanings, several months storage in the dark, and 80-hour exposure to ultraviolet light in a fadeometer. It is of interest to note that the washings removed all the residual soluble ammonium dicyanamide Without affecting moth repellency ofthe cloth.

In this method of application the aqueous dicyanamide solution should be sufiiciently concentrated to impregnate the wool with at least 2% of dicyanamide salt based on the weight of the wool. Thus, if desired, a 1% aqueous solution of ammonium dicyanamide can be used by adjusting the squeeze rolls to leave the wool impregnated with about 200 g. of solution per 100 g. of wool. On drying, this results in impregnating the wool with 2% of its weight of soluble dicyanamide salt, which is about the minimum percentage (with or without washing) that will give satisfactory moth repellency.

Using a procedure analogous to that of Example 1, a woolen flannel was treated with a 8% aqueous solution of sodium dicyanamide and run through squeeze rolls to leave 8% sodium dicyanamidein the cloth, based on the weight of the cloth. After drying in .a steam chest, part of the cloth was washed and soaped. Samples of the unwashed cloth and-the washed cloth were then tested in the usual way, and it was found that the unwashed cloth (whole circle) gave 0.3 mg. of frass, while the washed samples (whole circle) gave 2.0 mg. of frass. A similar experiment using 8% calcium dicyanamide was performed, giving 1.5 mg. of frass for the unwashed samples and 2.5 mg. of frass for the washeds'amples. In an experiment using 4% potassium dicyanamide, using the same procedure as Example I, washed samples gave 2.5 mg. of frass in the wholecircle test. Similar excellent results are obtained with lithium, barium, or magnesium dicyanamide.

EXAMPLE 2 Dye bath (exhaustion) application An alternate method of application of the dicyanamides, the exhaustion method, is equivalent to ordinary acid dyeing of wool wherein diluted dyestuff solutions are exhausted onto wool from an acid medium starting cold and bringing up to the boil in 30 minutes and thereafter continuing boiling for from 1 to 4 hours. The dicyanamides can be applied by this method using conventional acids, such as sulfuric or acetic acids. Sulfuric acid is preferred. A dilute aqueous solution containing from 2 to 8% dicyanamide salt based on the weight of the cloth is employed at a water/ cloth ratio of, for example, 30/1. In this procedure, acetic, sulfuric or other acid is added in amounts preferably at least equivalent to the content of the dicyanamide.

For a combined moth proofing and dyeing treatment the pH of the bath is preferably varied from pH 6 to pH 2 by the addition of the suitable acids that are required for the type of dye being used. The presence of sodium sulfate in the dyebath is not detrimental. The dyeing is carried out by slowly raising the dyebath to the boil and continuing the boiling for 60 to 90 minutes. The cloth is then rinsed and dried at any convenient'temperature.

The following typical bath formulation, using ammonium dicyanamide, was used in one run:

1 Added to simulate mill acid dyeing procedure.

The 9" x 23" sample was immersed in the bath at room temperature, the temperature was raised to the boil in 30 minutes, and this temperature was maintained for from 1 to 4 hours. After boiling, the samples were rinsed by one of the following alternate procedures:

1. (a) Discard /2 of the liquor, replace with cold water and stir for five minutes.

(11) Repeat (a).

(0) Repeat (b).

(d) Discard all water, replace with cold water, and stir for five minutes.

(:2) Centrifuge or squeeze out excess water.

(f) Dry 9 minutes at 250 F. slack or framed.

2. (a) Discard all water, replace with cold water, and stir for five minutes.

(b) Repeat (a).

(c) Repeat (b).

(a') Centrifuge or squeeze out excess water.

(e) Dry 9 minutes at 250 F. slack or framed.

Method 1 simulates mill practice of running in cold water while running out an equivalent amount of hot spent dye liquor; method 2 is more convenient on a smaller scale.

Using the dye bath technique outlined above, satisfacto'ry mothproofing results were obtained with 8%, 4%, and 2% ammonium dicyanamide applied either cold or at the boil, and whether rinsed before drying or not. (The percentages are based on the cloth weight.) Some of theresults are shown in the following'table.

DYE BATH APPLICATIONS OF AMMONIUM DIOYANAMIDE Weight of Frass (ma) er 5 Concenmused Washes When Cone. of N H4N (ON), tration-of Before N H4N(CN)2 Ap- Applied (Percent) Egg, Drying plied Cold At Boil 8. 9 Yes 1. 8 1. 7 6. 2 Yes 2. 6 0. 9 8. 9 No 1. 1 l. 2 v 6. 2 NO 1.8 2. 5

The other water soluble dicyanamides can be used with analogousresults.

EXAMPLE 3 Carbonizing after mothproo/ing Wool flannel that had been treated with ammonium dicyanamide by the dye both method and dried was treated with'a 4% sulfuric acid ca'rbonizing bath followed by drying'9 minutes at 250 F. The carbonized cloth was then neutralized with ammonium hydroxide, rinsed in cold water, and redried 9 minutes at 250 F. Satisfactory mothproofiing was obtanied after 5 washes for W001 flannel treated in this manner.

Wool flannel that had been treated with ammonium dicyanamide by the dip-pad method was treated before drying with a 4% sulfuric acid carboniz'ing bath. Following carbonizing, the cloth was rinsed in cold water and dried 9 minutes 'at 250 F. Mothproofi'ng after 5 washes was satisfactory on the samples thus treated. The results of these carbonizing tests are shown -in-the following table.

SULFUR-IO ACID CARBONIZING 1F WOOL FLANNEIQ TREATED WITH AMMONIUM DICYANAMIDE Application with? acid find'chroine dyes Ammonium dicyanamide was applied toswool flannel at 4% and 8% (percent of cloth weight) in a sulfuric acid. dye bath using 2% Calcocid Orange Y Ex. Cone. in the following formulations:

Percent Based on Weight of Cloth Ingredient Bath No. 1 Bath No. 2 Bath No.3

Dyestufi' 2 2 NH4N(CN )1 (100%) 8 4 NMSOA (100%)- 10 10 10 H18 04 (96.3%) 8. 9 6. 4 4. 0 Water to make 780 780 780 Mothproofing tests were satisfactory both before and after washing. The dycstuif did not impart mothproofing unless applied with ammonium dicyanamide. These results are shown in the following table.

EFFECT OF OALCOCID ORANGE Y EX. GONG. ON MOTH- PROOFING WITH AMMONIUM DICYANAMIDE IN DYE BATH APPLICATION Carpet Beetle Tests, Amount of NH4N(CN): A pplied (Percent of might (mg') Cloth Weig t) Unwashed Washes 8 2. 1 2. 2 4 l. 7 2. 1 0. 14. 0 8. 6 Untreated Control 13. 5 20. 3

EXAMPLE 5 Dye bath applications of 2% ammonium dicyanamide (based on cloth weight) were made to two samples of wool flannel using sulfuric acid and 2% of Calcohrome Yellow G. One sample was subsequently top-chromed. Mothproofing tests after 5 washes were satisfactory in both cases.

EXAMPLE 6 Effect of steaming Samples of wool flannel treated with 8% of ammonium dicyanamide (based on weight of cloth) were steamed for both 15 and 60 minutes at 20 pounds pressure without impairment of the mothproofing. For the sample steamed 15 minutes, the weight of frass was 1.4 mg., while for the sample steamed 60 minutes, the weight was 1.6 mg.

While good moth-repellency is imparted to wool by 2% aqueous metal dicyanamide salts (based on'cloth weight), the best results are obtained with 48% concentrations. Higher concentrations can be used, c. g., up to 50%, and even higher but oflfer no increased advantage as regards repellency, and merely add to the cost of the process.

Somewhat improved repellency results when the dicyanamide salt is used in conjunction with a stoichiometric equivalent of acid. The acid can be present in the di- 6 cyanamide salt solution or can be applied to the wet fabric after it is removed from the solution. The acid is preferably a strong acid such as sulfuric, hydrochloric, phosphoric, or the like. Sulfuric acid enhances the inherent efficacy of the dicyanamide salt solution in concentrations of 2% dicyanamide salt and up, based on cloth weight. The weaker acids, such as acetic, are not so effective in increasing repellency when using them with dicyanamide salt concentrations of 2% (based on cloth weight), but do increase inherent repellency when the dicyanamide salt concentrations is 4% and higher (based on cloth weight).

The preferred salt, ammonium dicyanamide, can be conveniently prepared from zinc dicyanamide as follows. /2 mole of zinc dicyanamide is suspended in 500 cc. of water. To this suspension is added in one quantity 276 cc. (1.0 mole) of a standard ammonium hydroxide solution (200 cc. of cone. aqueous ammonia diluted with 400 cc. of water). To the ammonia solution is added 232 cc. of water, and the reaction mixture is stirred for 20 minutes. The zinc hydroxide is removed by filtration and the filtrate evaporated to dryness under reduced pressure (water pump) at 60 C. A preliminary precipitate which may appear is zinc dicyanamide and should be removed before concentrating further. A yield of 74 grams (88%) of White, crystalline ammonium dicyanamide is obtained.

The other water soluble dicyanamide salts can be prepared by methods Well known in the art.

Adjuvants may be added to the dicyanamide salt solution as desired or as conditions may require. These may include buffering agents, e. g., hexamethylene tetramine, or other agents which will bring the composition to the particular pH desired for application of the composition to the textile material to be treated. The solution also may contain pigments, dyes, softeners, penetrating agents or other insecticides, bactericides or fungicides, or other adjuvants employed in textile treating materials including surface-active agents, e. g., dioctyl sodium sulfosuccinate, isopropylnaphthalene sodium sulfonate, etc.

After the woolen fabric or other wool-containing textile material has been treated with a water-soluble dicyanamide salt in the one of the ways above described, it may be given a mild soaping treatment to render it softer and more pliable. It then may be given the usual finishing treatments such as decatizing, brushing, shearing, pressing, etc. The process may be applied to colored goods as well as to raw or white woolens or the like without appreciably afiecting the color or shade and without damage to the material.

We claim:

1. A process for mothproofing keratinaceous materials subject to attack by larvae of clothes moths, carpet beetles, and their allies, which comprises immersing such material in an aqueous solution of a dicyanamide salt, said water soluble salt having the formula: M6[N(CN)2]2, were Me is a radical selected from the group consisting of ammonium, an alkali metal, and an alkaline earth metal and x is an integer corresponding to the valence of Me as defined, withdrawing said material from the solution and hot draft drying the same.

2. The method of mothproofing woolen fabrics which comprises immersing the fabric in an aqueous solution of a dicyanamide salt, said water soluble salt having the formula. Me[N(CN)z]x, Where Me is a radical selected from the group consisting of ammonium, an alkali metal, and an alkaline earth metal and x is an integer corresponding to the valence of Me as defined, withdrawing said fabric from the solution and hot draft drying the same.

3.The method according to claim 2 in which the fabric is immersed in at least 2% of its weight of ammonium dicyanamide.

4. The method according to claim 2 in which the fabric is immersed in at least 2% of its weight of calcium dicyanamide.

5. The method according to claim 2 in which the fabric is immersed in at least 2% of its weight of sodium dicyanamide.

6. The method according to claim 2 in which the fabric is immersed in at least 2% of its weight of potassium dicyanamide. V

7. The method according to claim 2 in which the fabric is immedsed in at least 2% of its weight of magnesium dicyanamide.

8. The method of mothproofing materials containing keratinaceous fabrics that comprises immersing the said materials in an aqueous solution of ammonium dicyanamide for a sutficient length of time to permit the keratinaceous fibers to become thoroughly Wetted, followed by removing the thus treated material and hot draft drying the same; the ammonium dicyanamide solution being sufliciently concentrated to leave at least 2% of ammonium dicyanamide on the fibers on removal from solution.

9. The method according to claim 8 in which the ammonium dicyanamide solution is sufliciently Concentrated to leave at least 4% of ammonium dicyanamide on the fibers on removal from solution.

10. The method of mothproofing a material containing keratinaceous fiber subject to attack by clothes moth larvae that comprises immersing the said material in an aqueous solution containing '2'8% ammonium dicyanamide based on the weight of the material and sufficient acid to react with the ammonia content of the said ammon'ium -dicyanamide, withdrawing said fiber from the solution and hot draft drying the same.

References Cited in-the file of this patent UNITED STATES PATENTS OTHER REFERENCES Gould: Soap and Sanitary Chemicals, volume 24,

Number 3, pages 147, 149, 177, 179, March 1948. 

1. A PROCESS FOR MOTHPROOFING KERATINACEOUS MATERIALS SUBJECT TO ATTACK BY LARVAE OF CLOTHES MOTHS, CARPET BEETLES, AND THEIR ALLIES, WHICH COMPRISES IMMERSING SUCH MATERIAL IN AN AQUEOUS SOLUTION OF A DICYANAMIDE SALT, SAID WATER SOLUBLE SALT HAVING THE FORMULA: ME(N(CN)2)X, WHERE ME IS A RADICAL SELECTED FROM THE GROUP CONSISTING OF AMMONIUM, AN ALKALI METAL, AND AN ALKALINE AARTH METAL AND X IS AN INTERGER CORRESPONDING TO THE VALENCE OF ME AS DEFINED, WITHDRAWING SAID MATERIAL FROM THE SOLUTION AND HOT DRAFT DRYING THE SAME. 